1. Field of the Invention
This invention relates to an auxiliary worm gear speed reducer unit that is attached by use of an adapter member to a main worm gear speed reducer unit to form a double speed reducer unit assembly.
2. Description of the Prior Art
It is well known to connect in a suitable manner the worm, or input, shaft of a worm gear speed reducer unit to the output, or drive, shaft of a primary drive unit, such as a motor, for speed reduction purposes. Rotation of the motor output shaft causes rotation of the worm gear, or output, shaft of the worm gear speed reducer unit at a speed lower than the speed of the output shaft of the motor. It is also well known to connect, in a suitable manner, the worm gear, or output, shaft of a first speed reducer unit to the worm, or input, shaft of a second worm gear speed reducer unit to obtain a further speed reduction, as shown, for example, in the U.S. Pat. No. 1,330,869. The worm gear, or output, shaft of the second unit rotates, in use, at a greatly reduced speed. Different coupling devices have been used to couple the worm gear, or output, shaft of the first worm gear reducer unit to the worm, or input, shaft of the second worm gear reducer unit. One drawback of such couplings is that the coupling shafts are difficult to precisely align, and the couplings add cost to the assembly. It is also known, in other types of two stage speed change mechanisms, to connect the two stages with a common shaft as shown, for example, in the application of Avramidis et al, Ser. No. 343,329, filed Mar. 21, 1973, and assigned to the same assignee as the assignee of the present invention.